Blending of summer gasoline containing ethanol

ABSTRACT

Provided is a method for blending an unleaded summer gasoline containing ethanol. The method comprises providing a substantially oxygenate free unleaded gasoline blend stock having an RVP of no greater than 7.0, and preferably no greater than 6.0, and then adding sufficient ethanol to the gasoline blend stock such that the ethanol addition does not cause the T50 value to drop below the ASTM D 4814 minimum requirements of 170° F.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to fuels, particularly gasoline fuels which contain ethanol. More specifically, the present invention relates to a method of making a summer, low-emission gasoline fuel which contains ethanol and complies with the California Code of Regulations.

[0003] 2. Brief Description of the Related Art

[0004] One of the major environmental problems confronting the United States and other countries is atmospheric pollution caused by the emission of pollutants in the exhaust gases and gasoline vapor emissions from gasoline fueled automobiles. This problem is especially acute in major metropolitan areas where atmospheric conditions and the great number of automobiles result in aggravated conditions. While vehicle emissions have been reduced substantially, air quality still needs improvement. The result has been that regulations have been passed to further reduce such emissions by controlling the composition of gasoline fuels. These specially formulated, low emission gasolines are often referred to as reformulated gasolines. California's very strict low emissions gasoline is often referred to as California Phase 2 gasoline. One of the requirements of these gasoline regulations is that, in certain geographic areas, oxygen-containing hydrocarbons, or oxygenates, be blended into the fuel.

[0005] Congress and regulatory authorities, such as CARB (the California Air Resources Board), have focused on setting specifications for low emissions, reformulated gasoline. The specifications, however, require the presence of oxygenates in gasoline sold in areas that are not in compliance with federal ambient air quality standards for ozone, and the degree of non-attainment is classified as severe, or extreme. Among the emissions which the reformulated gasoline is designed to reduce, are nitrogen oxides (NO_(x)), hydrocarbons (HC), and toxics (benzene, 1,3-butadiene, formaldehyde and acetaldehyde). A reduction in these emissions has been targeted due to their obvious impact upon the air we breathe and the environment in general.

[0006] Oxygenated gasoline is a mixture of conventional hydrocarbon-based gasoline and one or more oxygenates. Oxygenates are combustible liquids which are made up of carbon, hydrogen and oxygen. All the current oxygenates used in reformulated gasolines belong to one of two classes of organic molecules: alcohols and ethers. The Environmental Protection Agency regulates which oxygenates can be added to gasoline and in what amounts.

[0007] The primary oxygen-containing compounds employed in gasoline fuels today are methyl tertiary butyl ether (MTBE) and ethanol. While oxygen is in most cases required in reformulated gasolines to help effect low emissions, the presence of ethers such as MTBE in gasoline fuels has particularly begun to raise environmental concerns. For example, MTBE has been observed in drinking water reservoirs, and in a few instances, ground water in certain areas of California. As a result, the public is beginning to question the benefits and/or importance of having an ether such as MTBE in cleaner burning gasolines, if the ether simply pollutes the environment in other ways.

[0008] Thus, while some of the concerns with regard to gasoline fuels containing ethers, could be overcome by further safe handling procedures and the operation of present facilities to reduce the risk of any spills and leaks, there remains a growing public concern with regard to the use of ethers such as MTBE in gasoline fuels. In an effort to balance the need for lower emission gasolines and concerns about the use of ethers it, therefore, would be of great benefit to the industry if a cleaner burning gasoline without ethers, which complied with the requirements of the regulatory authorities (such as CARB), could be efficiently made.

[0009] Replacing ethers such as MTBE with ethanol is one possibility to reducing the use of MTBE. However, the use of ethanol presents other problems, particularly in its handling and transportation. Transporting a gasoline containing ethanol from a refinery to a terminal, particularly through a pipeline, often results in the ethanol picking up water. This results in the final gasoline not meeting the specifications required, e.g., by the California Code of Regulations. As well, rust in the pipeline can be loosened by the ethanol, resulting in further contamination of the gasoline.

[0010] The replacement of ethers with ethanol in the blending of gasolines which meet the California Code of Regulations, therefore, still requires the need to resolve several major problems. Because of the importance ethanol is beginning to play in oxygenated gasoline, a resolution of these problems would be of great interest to the industry.

[0011] It is therefore an object of the present invention to provide a method of blending ethanol into a gasoline formulation while overcoming the foregoing problems.

[0012] It is yet another object of the present invention to provide a novel method for obtaining a gasoline formulation containing ethanol which meets the California Code of Regulations.

[0013] Yet another object of the present is to provide a method of blending a gasoline formulation containing ethanol at a site remote from the refinery, which formulation meets the California Code of Regulations.

[0014] These and other objects of the present invention will become apparent upon a review of the following description, the figures of the drawing, and the claims appended hereto.

SUMMARY OF THE INVENTION

[0015] In accordance with the foregoing objectives, there is provided by the present invention a method for blending unleaded gasoline containing ethanol, and having A Reid Vapor Pressure (RVP) in pounds per square inch (psi) of 8.0 or less, and more preferably 7.0 or less. The method comprises providing a substantially oxygenate free unleaded gasoline blend stock which has an RVP of no greater than 7.0, and more preferably no greater than 6.0. Ethanol is then added to the gasoline blend stock in an amount such that the final gasoline meets the California Code of Regulations, with the unleaded gasoline blend stock to which the ethanol is added having a T50 sufficiently high such that the ethanol addition does not cause the T50 value to drop below the ASTM D 4814 minimum requirement of 170° F. In a preferred embodiment, the amount of ethanol added is at least 2.0 volume percent based on the final gasoline.

[0016] Among other factors, the present invention is based upon the discovery that the addition of ethanol to a gasoline blend stock cannot be a linear addition, for the specifications of the gasoline are changed non-linearly when ethanol is added. The specifications of the gasoline blend stock must therefore be controlled in order to compensate for the addition of ethanol. This is particularly true for the RVP and T50 characteristics of the gasoline. The present invention, therefore, blends ethanol with a gasoline blend stock which has an RVP sufficiency low and a T50 specification sufficiently high such that the addition of the desired amount of ethanol results in a gasoline which is in compliance with the California Code of Regulations. It is the discovery of the need to so control the RVP and T50 specifications of the gasoline blend stock which permits one to successfully blend the ethanol into a compliant gasoline formulation.

[0017] In a preferred embodiment, the present invention allows one to blend a gasoline blend stock having predetermined RVP and T50 specifications at a refinery which does not contain ethanol, transport the blend stock through a pipeline to a terminal, and mix the ethanol and blend stock at the terminal with confidence that the final gasoline composition meets the California Code of Regulations. This method allows one to avoid the problems inherent in the transporting of an ethanol containing gasoline formulation, while meeting all required specifications for the gasoline.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING

[0018]FIG. 1 schematically depicts a gasoline blending system useful in preparing the blend stock of the present invention.

[0019]FIG. 2 graphically depicts the distillation curves for the gasoline blending components.

[0020]FIG. 3 graphically depicts the distillation curves for a gasoline blend stock blended with various amounts of ethanol.

[0021]FIG. 4 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0022]FIG. 5 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0023]FIG. 6 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0024]FIG. 7 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0025]FIG. 8 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0026]FIG. 9 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0027]FIG. 10 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0028]FIG. 11 graphically depicts the distillation curves, for another gasoline blend stock blended with various amounts of ethanol.

[0029]FIG. 12 graphically depicts the vapor pressure curves for gasoline blend stocks blended with various amounts of ethanol.

[0030]FIG. 13 graphically depicts the temperature for vapor-liquid ratio of 20 curves for gasoline blend stocks blended with various amounts of ethanol.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0031] Gasolines are well known fuels, generally composed of a mixture of numerous hydrocarbons having different boiling points at atmospheric pressure. Thus, a gasoline fuel boils or distills over a range of temperatures, unlike a pure compound. In general, a gasoline fuel will distill over the range of from about, room temperature to 437° F. (225° C.). This temperature range is approximate, of course, and the exact range will depend on the conditions that exist in the location where the automobile is driven. The distillation profile of the gasoline can also be altered by changing the mixture in order to focus on certain aspects of gasoline performance, depending on the time of year and geographic location in which the gasoline will be used.

[0032] Gasolines are therefore, typically composed of a hydrocarbon mixture containing aromatics, olefins, naphthenes and paraffins, with reformulated gasoline most often containing an oxygen compound. The fuels contemplated in the present invention are substantially ether free unleaded gasolines (herein defined as containing a concentration of lead no greater than 0.05 gram of lead per gallon which is 0.013 gram of lead per liter), which contain ethanol as the oxygen compound. The anti-knock value (R+M)/2 for regular gasoline is generally at least 87, at least 89 for mid-range, and for premium at least 91.

[0033] In an attempt to reduce harmful emissions upon the combustion of gasoline fuels, regulatory boards as well as Congress have developed certain specifications for reformulated gasolines. One such regulatory board is that of the State of California, i.e., the California Air Resources Board (CARB). In 1991, specifications were developed by CARB for California gasolines which, based upon testing, should provide good performance and low emissions. The specifications and properties of the reformulated gasoline, which is referred to as the Phase 2 reformulated gasoline or California Phase 2 gasoline, are shown in Table 1 below. TABLE 1 Properties and Specifications for Phase 2 Reformulated Gasoline Flat Averaging Cap Fuel Property Units Limit Limit Limit Reid vapor pressure psi, max. 7.00¹ 7.00 (RVP) Sulfur (SUL) ppmw 40 30 80 Benzene (BENZ) vol. %, max. 1.00 0.80 1.20 Aromatic HC (AROM) vol. %, max. 25.0 22.0 30.0 Olefin (OLEF) vol. %, max. 6.0 4.0 10.0 Oxygen (OXY) wt. % 1.8 0 (min) (min) 2.7 2.2 (max)² (max) Temperature at 50% deg. F. 210 200 220 distilled (T50) Temperature at 90% deg. F. 300 290 330 distilled (T90)

[0034] In Table 1, as well as for the rest of the specification, the following definitions apply:

[0035] Aromatic hydrocarbon content (Aromatic HC, AROM) means the amount of aromatic hydrocarbons in the fuel expressed to the nearest tenth of a percent by volume in accordance with 13 CCR (California Code of Regulations), section 2263.

[0036] Benzene content (BENZ) means the amount of benzene contained in the fuel expressed to the nearest hundredth of a percent by volume in accordance with 13 CCR, section 2263.

[0037] Olefin content (OLEF) means the amount of olefins in the fuel expressed to the nearest tenth of a percent by volume in accordance with 13 CCR, section 2263.

[0038] Oxygen content (OXY) means the amount of actual oxygen contained in the fuel expressed to the nearest tenth of a percent by weight in accordance with 13 CCR, section 2263.

[0039] Potency-weighted toxics (PWT) means the mass exhaust emissions of benzene, 1,3-butadiene, formaldehyde, and acetaldehyde, each multiplied by their relative potencies with respect to 1,3-butadiene, which has a value of 1.

[0040] Predictive model means a set of equations that relate emissions performance based on the properties of a particular gasoline formulation to the emissions performance of an appropriate baseline fuel.

[0041] Reid vapor pressure (RVP) means the vapor pressure of the fuel expressed to the nearest hundredth of a pound per square inch in accordance with 13 CCR, section 2263.

[0042] Sulfur content (SUL) means the amount by weight of sulfur contained in the fuel expressed to the nearest part per million in accordance with 13 CCR, section 2263.

[0043] 50% distillation temperature (T50) means the temperature at which 50% of the fuel evaporates expressed to the nearest degree Fahrenheit in accordance with 13 CCR, section 2263.

[0044] 90% distillation temperature (T90) means the temperature at which 90% of the fuel evaporates expressed to the nearest degree Fahrenheit in accordance with 13 CCR, section 2263.

[0045] Toxic air contaminants means exhaust emissions of benzene, 1,3-butadiene, formaldehyde, and acetaldehyde.

[0046] The pollutants addressed by the foregoing specifications include oxides of nitrogen (NO_(x)), and hydrocarbons (HC), which are generally measured in units of g/mile, and potency-weighted toxics (PWT), which are generally measured in units of mg/mile.

[0047] The California Phase 2 reformulated gasoline regulations define a comprehensive set of specifications for gasoline (Table 1). These specifications have been designed to achieve large reductions in emissions of criteria and toxic air contaminants from gasoline-fueled vehicles. Gasolines which do not meet the specifications are believed to be inferior with regard to the emissions which result from their use in vehicles. All gasolines sold in California, beginning June 1, 1996, have had to meet CARB's Phase 2 requirements as described below. The specifications address the following eight gasoline properties:

[0048] Reid vapor pressure (RVP)

[0049] Sulfur

[0050] Oxygen

[0051] Aromatic hydrocarbons

[0052] Benzene

[0053] Olefins

[0054] Temperature at which 90 percent of the fuel has evaporated (T90)

[0055] Temperature at which 50 percent of the fuel has evaporated (T50)

[0056] The Phase 2 gasoline regulations include gasoline specifications that must be met at the time the gasoline is supplied from the production facility. Producers have the option of meeting either “flat” limits or, if available, “averaging” limits, or, alternatively a Predictive Model equivalent performance standard using either the “flat” or “averaging” approach.

[0057] The flat limits must not be exceeded in any gallon of gasoline leaving the production facility when using gallon compliance. For example, the aromatic content of gasoline, subject to the default flat limit, could not exceed 25 volume percent (see Table 1).

[0058] The averaging limits for each fuel property established in the regulations are numerically more stringent than the comparable flat limits for that property. Under the averaging option, the producer may assign differing “designated alternative limits” (DALs) to different batches of gasoline being supplied from the production facility. Each batch of gasoline must meet the DAL assigned for the batch. In addition, a producer supplying a batch of gasoline with a DAL less stringent than the averaging limit must, within 90 days before or after, supply from the same facility sufficient quantities of gasoline subject to more stringent DALs to fully offset the exceedances of the averaging limit. Therefore, an individual batch may not meet the California Predictive Model when using averaging, but in aggregate, over time, they must.

[0059] The Phase 2 gasoline regulations also contain “cap” limits. The cap limits are absolute limits that cannot be exceeded in any gallon of gasoline sold or supplied throughout the gasoline distribution system. These cap limits are of particular importance when the California Predictive Model or averaging is used.

[0060] A mathematical model, the California Predictive Model, has also been developed by CARB to allow refiners more flexibility. Use of the predictive model is designed to allow producers to comply with the Phase 2 gasoline requirements by producing gasoline to specifications different from either the averaging or flat limit specifications set forth in the regulations. However, producers must demonstrate that the alternative Phase 2 gasoline specifications will result in equivalent or lower emissions compared to Phase 2 gasoline meeting either the flat or averaging limits as indicated by the Predictive Model. Further, the cap limits must be met for all gasoline formulations, even alternative formulations allowed under the California Predictive Model. When the Predictive Model is used, the eight parameters of Table 1 are limited to the cap limits.

[0061] In general, the California Predictive Model is a set of mathematical equations that allows one to compare the expected exhaust emissions performance of a gasoline with a particular set of fuel properties to the expected exhaust emissions performance of an appropriate gasoline fuel. One or more selected fuel properties can be changed when making this comparison.

[0062] Generally, in a predictive model, separate mathematical equations apply to different indicators. For example, a mathematical equation could be developed for an air pollutant such as hydrocarbons; or, a mathematical equation could be developed for a different air pollutant such as the oxides of nitrogen.

[0063] Generally, a predictive model for vehicle emissions is typically characterized by:

[0064] the number of mathematical equations developed,

[0065] the number and type of motor vehicle emissions tests used in the development of the mathematical equations, and

[0066] the mathematical or statistical approach used to analyze the results of the emissions tests.

[0067] The California Predictive Model is comprised of twelve mathematical equations. One set of six equations predicts emissions from vehicles in Technology Class 3 (model years 1981-1985), another set of six is for Technology Class 4 (model years 1986-1993). For each technology class, one equation estimates the relative amount of exhaust emissions of hydrocarbons, the second estimates the relative amount of exhaust emissions of oxides of nitrogen, and four are used to estimate the relative amounts of exhaust emissions of the four toxic air contaminants: benzene, 1,3-butadiene, acetaldehyde, and formaldehyde. These toxic air contaminants are combined based on their relative potential to cause cancer, which is referred to as potency-weighting.

[0068] In creating the California Predictive Model, CARB compiled and analyzed the results of over 7,300 vehicle exhaust emissions tests. A standard statistical approach to develop the mathematical equations to estimate changes in exhaust emissions was used based upon the data collected. It is appreciated that the California Predictive Model might change with regard to certain of the qualities considered. However, it is believed that the present invention and its discovery that a blending process can be used to effectively create the gasolines of the present invention, can be used to blend a gasoline in compliance with the specifications of any California Predictive Model.

[0069] In summary, specific requirements were created by the California Air Resources Board to restrict the formulation of gasoline to ensure the production of gasoline which produces low emissions when used in automobiles.

[0070] The present invention provides one with a method of blending a low emission, ether free gasoline economically and in a commercially plausible manner, which gasoline has an RVP suitable for the summer season. The gasoline obtained is in compliance with the California Code of Regulations for reformulated gasoline and the California Predictive Model, and it contains substantially no ethers. The gasoline is also in compliance with ASTM D 4814.

[0071] By substantially free of ethers, for the present invention, is meant that there is less than 0.1 wt. %, more preferably less than 0.05 wt %, and most preferably less than 0.01 wt % of ether compounds in the blended gasoline. The gasoline does contain ethanol as a substantial replacement for the ether such as MTBE.

[0072] The gasoline of the present invention is also most preferably low in sulfur content, with the sulfur content being about 30 ppm or less. It is preferred that the sulfur content is less than 20 ppm, more preferably less than 15 ppm, even more preferably less than 10 ppm, more preferably less than 5 ppm, and most preferably less than 1 ppm. The amount of sulfur can be controlled by specifically choosing streams which are low in sulfur for blending in the gasoline. It has been found that the use of low sulfur permits one to more easily and economically blend a gasoline with low emissions. Thus, the low sulfur content is a preferred aspect of the present invention.

[0073] The final gasoline compositions of the present invention also preferably have a T50 of less than 210° F., or preferably less than 200° F., and most preferably about 185° F. or less. The olefin content is also less than 8 vol %, more preferably less than 6 vol %, and most preferably less than 3 vol %. The amount of benzene is also less than 0.7 wt % and less than 0.5 wt % in the most preferred embodiment.

[0074] The gasoline of the present invention can also be blended to achieve any octane rating (R+M)/2 desired. A regular gasoline with an octane rating of at least 87, a mid-grade gasoline with an octane rating of at least 89 or 90, or a premium gasoline with an octane rating of at least 91 can all be prepared in accordance with the present invention.

[0075] The method of the present invention comprises continuously blending gasoline component streams from a refinery process plant to prepare a gasoline blend stock. The blend stock will generally have an RVP value no greater than 5.5 to 7.0 psi, more preferably in the range of from about 5.5 to 6.5, and most preferably an RVP of about 6.0 or less, e.g., in the range of from about 5.5 to 6.0; and, a T50 value sufficiently high such that the addition of ethanol does not cause the T50 value to drop below the ASTM D 4814 minimum requirement of 170° F. Generally the T50 value for the blend stock is at least 190° F. Any of the conventional gasoline component streams which are blended into gasolines can be used.

[0076] A preferred blend stock gasoline composition of the present invention has an RVP of less than 6.0 psi, a T50 value of greater than 190° F, and a sulfur content of no greater than 30 ppm sulfur, more preferably less than 20 ppm sulfur, and most preferably less than 10 ppm sulfur. The amount of ethanol that is blended with such a blend stock is preferably in the range of from 2.0 to 6.0 vol %.

[0077] The specific amount of ethanol that can be blended with a particular blend stock can be determined by creating a model from a number of runs as shown in the examples. Once such a model is created, the desired amount of ethanol can be determined and blended according to the model in order to meet the RVP and T50 California Code requirements in accordance with the model.

[0078] A schematic of a suitable system for blending the gasoline blend stock is shown in FIG. 1 of the Drawing. The gasoline component streams are provided at 1, and flow through component pump and flow meters 2. Component control valves 3 control how much of each stream is let into the blending process 4, to create the blended gasoline. The blended gasoline is then generally stored in a gasoline product tank 5.

[0079] To begin the process, a blending model can be used to approximate the blending of the gasoline feed stock. Such blending models can be created via experience of blending gasoline feed stocks together with ethanol. Such experience can be gained from the examples which follow.

[0080] It is generally important to include an analysis of the blended gasoline feed stock. Such testing can be periodic or continuous. In general, it is preferred to use an on-line analyzer as shown at 6. Generally, the analysis run involves the entire boiling range of the gasoline, including T50 and T90, the RVP of the blended gasoline, the benzene/aromatics content and the sulfur content. The tests run can be as follows:

[0081] For distillation, the analyzer utilizes an Applied Automation Simulated Distillation Motor Gasoline Gas Chromatograph. This analyzer is similar to the instrument described in ASTM D 3710-95: Boiling Range Distribution of Gasoline by Gas Chromatography. This test method is designed to measure the entire boiling range of gasoline, either high or low Reid Vapor Pressures, and has been validated for gasolines containing the oxygenates methyl tertiary butyl ether (MTBE) and tertiary amul methyl either (TAME). Alternatively, the ASTM D 86 distillation method can be used, although not preferred for an on-line analyzer. Either test can be run.

[0082] Measuring RVP utilizes an ABB Model 4100 Reid Vapor Pressure Analyzer. This analyzer is described in ASTM D 5482-96. This is a substitute for the “CARB RVP” calculation based on the Dry-Vapor Pressure result from D 5191. Either can be used.

[0083] The method for measuring benzene and aromatic content can utilize the Applied Automation Standard Test Method for Determination of Benzene, Toluene, C8 and Heavier Aromatics, and Total Aromatics in Finished Motor Gasoline Gas Chromatograph. The analyzer is similar to the instrument described in ASTM D 5580-95: Standard Tests Method for Determination of Benzene, Toluene, Ethylbezene, p/m-Xylene, C9 and Heavier Aromatics, and Total Aromatics in Finished Gasoline by Gas Chromatography. This is a substitute for ASTM D 5580 and ASTM D 1319 (for aromatics) and ASTM D 3606 (for benzene) methods which methods can also be used.

[0084] Olefin content can be measured using an Applied Automation Olefins Gas Chromatograph. The method is a simplified version of the PIONA method. This is substitute for ASTM D 1319 method which can also be used.

[0085] For measurement of sulfur content, the analyzer can utilize an ABB Model 3100 Sulfur in Gasoline Gas Chromatograph. The method is designed to quantify the amount of sulfur in a hydrocarbon steam as a substitute for the ASTM D 2622 method, which can also be used.

[0086] The information from the analysis is then fed to a computer 7 which can control the component flows to produce a gasoline blend which complies with the California Predictive Model for the summer season. The information provided to the computer can comprise information from on-line analysis, as well as information from an analysis conducted in a laboratory 8. If desired, tank information and blend specifications for the gasoline in the product tank can also be provided to the computer. Samples can be drawn from the gasoline product tank, for example, at 9, for laboratory testing.

[0087] Once the feed stock is blended, it can be mixed directly with the desired amount of ethanol for which the feed stock has been blended, or simply transported, e.g., through a pipeline, to a terminal. Mixing of the ethanol with the feed stock can then be accomplished at the terminal in accordance with the present invention.

EXAMPLES

[0088] Several blended gasoline feed stocks were made to create a model. The various component streams used were conventional gasoline component streams including: (i) whole alkylate; (ii) FCC gasoline; (iii) hydrobate; (iv) pentane/hexane isomerate; (v) heavy reformate; (vi) hydrotreated FCCL; and (vii) alkylate.

[0089] In a blending system, all of the foregoing component streams are preferably provided from the same refinery. However, any one of the streams used can be provided from an outside source, but it is preferred for the present invention that the component streams originate as streams in the refinery on site. For the present examples, small samples were used on a laboratory scale in order to create a model.

[0090] The characteristics of such various component streams are provided in Table 2 below. The relative amounts of each component in each blended feed stock for the examples is also provided in Table 3.

[0091] Once each of the blend stocks were made, it was mixed with 2% by volume, 4%, 6% and 10% ethanol. The resulting final gasoline specifications were then measured and are reported in Table 4 below. The results are graphically presented in FIGS. 2-13. Table 4 and the graphs of FIGS. 2-13 can be used as a model in determining an appropriate amount of ethanol to be blended with a particular blend stock. TABLE 2 ETHANOL BLENDING STUDY COMPONENT INSPECTIONS Whole FCC PenHex/ Heavy Hydrotreated Component Alkylate Gasoline Hydrobate Isomerate Reformate FCCL Alkylate Vapor Pressure, psi 6.0 3.5 2.0 11.8 1.0 2.4 7.7 D 86 Distillation ° F. IBP 98 98 127 130 180 178 93 94 215 215 159 160 94 94  5% Evaporated 136 139 168 166 205 205 109 109 231 229 184 184 123 124 10% Evaporated 152 154 179 178 210 209 112 112 234 234 193 192 134 134 20% Evaporated 172 175 194 194 215 213 116 116 238 238 204 204 149 149 30% Evaporated 197 199 212 211 222 221 119 120 243 242 219 219 168 170 40% Evaporated 214 215 233 231 228 227 124 124 248 248 240 240 190 193 50% Evaporated 223 223 254 254 235 234 128 129 256 255 266 267 208 209 60% Evaporated 228 228 279 278 243 243 134 135 263 264 295 296 218 218 70% Evaporated 234 233 300 299 254 253 142 142 275 274 324 321 227 226 80% Evaporated 241 241 321 322 266 267 150 150 287 288 352 352 238 236 90% Evaporated 258 258 345 345 284 285 162 161 306 305 380 380 259 260 95% Evaporated 296 293 360 360 298 298 173 172 321 322 399 400 297 296 End Point 388 387 384 383 321 322 182 206 380 385 421 422 380 372 % Rec 97.5 98.8 98 98.6 98.4 98.5 96.3 98.6 99 98.5 98.5 98.8 97.7 98.3 % Resid 1 1 1 1 1 1 2 1 0.6 1 1 1 1 1 % Loss 1.5 0.9 0 0.9 0.6 0.5 1.7 0.5 0.4 0.5 0.5 0.5 1.3 0.7 Hydrocarbon Type, vol % Aromatics 0.12 35.95 10.86 0.43 78.58 37.92 0.14 Olefins 0.02 20.35 0.46 0.18 0.33 0.4 0.01 n-paraffins 2.42 3.37 11.09 18.92 4.51 6.2 2.6 i-paraffins 93.88 25.64 33.38 61.24 15.19 34.83 93.03 Naphthenes 1.19 9.04 39.2 19.19 1.2 13.95 0.95

[0092] TABLE 3 ETHANOL BLENDING PROGRAM BASE FUEL BLENDS Blend 1 Blend 2 Blend 3 Blend 4 Blend 5 Blend 6 Blend 7 Blend 8 Blend 9 Component Vol % Vol % Vol % Vol % Vol % Vol % Vol % Vol % Vol % Whole Alkylate 27.85 28.79 5.34 2.42 16.59 0 0 0 0 FCC Gasoline 2.41 0 15.75 24 0 0 0 3.879 0 Hydrobate 0 22.71 11.97 11.31 8.31 0 0 14.96 0 PenHex/lsomerate 35.83 30.95 0 43.24 32.2 1.97 46.73 39.25 19.21 Heavy Reformate 2.48 14.05 10.12 19.03 18.86 31.69 29.04 36.86 44.37 Hydrotreated FCCL 31.63 3.5 0 0 24.04 0 24.23 5.05 0 Alkylate 0 0 56.82 0 0 66.35 0 0 36.42 Total 100 100 100 100 100 100 100 100 100

[0093] TABLE 4 ETHANOL BLENDING PROGRAM BLEND INSPECTIONS Base 1 +2 +4 +6 +10 Base 2 +2 +4 +6 +10 Base 3 +2 +4 +6 +10 Vapor Pressure, psi 6.9 8 8.2 8.1 8.1 6.3 7.4 7.5 7.8 7.5 5.5 6.7 6.7 6.6 6.8 D 86 Distillation, ° F. Initial 107 103 111 105 103 105 104 107 104 108 104 107 105 108 111  5% Evaporated 134 121 121 122 115 135 127 128 126 128 144 132 132 132 135 10% Evaporated 141 129 126 127 125 146 136 131 132 133 157 143 138 138 139 15% Evaporated 147 136 130 130 129 153 145 135 136 137 167 156 140 142 143 20% Evaporated 152 144 133 132 131 160 154 140 136 140 177 170 151 147 147 25% Evaporated 159 153 136 135 135 168 164 149 142 144 187 183 171 154 151 30% Evaporated 165 161 150 138 136 176 174 164 149 147 197 195 189 175 155 35% Evaporated 173 169 162 146 141 184 183 178 166 151 206 204 202 197 180 40% Evaporated 181 177 173 163 144 193 191 188 183 156 213 213 210 209 187 45% Evaporated 189 188 183 176 147 201 200 197 195 171 219 218 217 216 211 50% Evaporated 199 195 192 189 152 209 208 206 204 198 224 224 222 221 220 55% Evaporated 209 205 203 200 177 216 215 214 212 211 229 228 227 226 225 60% Evaporated 219 216 214 211 199 223 222 221 220 219 234 233 232 231 228 65% Evaporated 230 228 228 223 212 230 229 228 227 225 238 238 238 237 235 70% Evaporated 242 240 238 238 225 236 236 235 234 233 245 245 244 243 242 75% Evaporated 256 253 250 249 238 243 244 242 242 240 252 252 251 250 249 80% Evaporated 272 269 267 268 253 252 252 250 251 250 262 261 261 259 259 85% Evaporated 296 292 290 288 272 263 263 261 262 260 276 275 276 273 274 90% Evaporated 333 327 326 324 299 279 280 275 278 276 297 295 297 293 294 95% Evaporated 385 386 366 340 307 308 301 307 303 325 329 322 End Point 365 371 370 374 373 314 315 307 319 305 325 373 332 372 326 % Recovered 95.0 95.0 95.1 95.0 95.0 94.9 95.0 95.0 94.9 94.9 94.6 99.0 94.9 99.0 95.0 Temperature for a Vapor-Liquid 151 138 134 134 133 157 144 139 138 137 168 153 148 144 143 Ratio of 20, ° F. Ethanol, vol % 0 1.16 3.23 5.3 9.33 0 1.39 3.41 5.25 9.66 0 1.15 3.5 5.1 9.85 Hydrocarbon Type, vol % Aromatics 16.11 15.57 15.27 14.96 14.62 15.72 15.41 15.16 14.94 14.28 16.2 16.17 15.37 15.46 14.31 Olefins 0.68 0.88 0.67 0.66 0.62 0.79 0.27 0.65 0.62 0.64 3.31 3.27 3.25 3.17 2.94 n-Paraffins 9.27 9.27 9.04 8.86 8.39 10.03 9.95 9.67 9.48 9.02 4.04 3.98 3.93 3.63 3.67 l-Paraffins 59.12 58.7 57.56 56.2 53.65 58.51 55.82 54.64 53.51 5.096 87.5 68.65 65.48 63.98 61.35 Naphthenes 11.76 11.4 11.34 11.13 10.63 15.2 15.37 14.65 14.46 13.8 6.39 6.31 6.12 6.03 5.63 Base 4 +2 +4 +6 +10 Base 5 +2 +4 +6 +10 Base 6 +2 +4 +6 +10 Vapor Pressure, psi 6.9 7.9 6 8 8 6.1 7.1 7.2 7.3 7.2 5.7 6.7 6.8 6.9 6.9 D 86 Distillation, ° F. Initial 103 101 105 105 107 105 107 107 106 112 100 103 104 109 107  5% Evaporated 131 123 122 123 125 138 128 127 128 129 141 131 132 132 134 l0% Evaporated 140 130 127 128 129 148 137 132 133 134 155 143 138 137 139 15% Evaporated 145 136 128 130 130 155 146 133 134 137 166 156 140 141 144 20% Evaporated 150 144 130 132 134 161 155 137 137 140 177 170 162 145 148 25% Evaporated 158 151 137 136 137 169 164 150 141 143 189 184 173 154 152 30% Evaporated 163 159 149 136 140 177 173 163 149 146 200 197 191 174 156 35% Evaporated 170 167 161 146 143 185 162 177 166 149 209 207 205 197 162 40% Evaporated 177 176 171 162 146 193 191 188 182 154 216 215 214 211 188 45% Evaporated 186 164 181 177 150 202 200 197 195 171 221 220 219 218 212 50% Evaporated 195 194 191 188 164 211 209 207 206 197 225 225 224 223 222 55% Evaporated 205 204 202 200 190 220 219 218 215 213 229 229 228 226 228 60% Evaporated 217 215 213 211 206 230 228 226 226 223 233 233 232 231 228 65% Evaporated 228 227 225 224 220 239 238 236 235 232 237 237 236 235 234 70% Evaporated 241 240 238 237 233 249 246 248 246 243 242 242 242 240 239 75% Evaporated 254 253 252 251 247 260 259 257 257 254 249 249 248 247 247 80% Evaporated 268 267 265 265 262 274 272 269 271 258 258 257 257 256 254 85% Evaporated 283 281 281 280 279 292 290 287 289 285 270 270 269 268 267 90% Evaporated 303 300 299 299 296 316 314 311 314 310 287 287 287 265 265 95% Evaporated 326 323 324 325 321 349 343 348 341 311 312 310 310 End Point 330 325 355 362 325 351 342 346 349 342 309 313 315 312 313 % Recovered 95.2 95.4 97.8 98 95.4 94.9 94.6 94.8 94.8 95.2 94.7 95 95 94.9 95 Temperature for a Vapor-Liquid 150 139 136 134 134 160 147 142 140 139 167 153 147 144 143 Ratio of 20, ° F. Ethanol, vol % 0 1.28 3.35 5.43 9.85 0 1.41 3.48 5.54 9.62 0 1.28 3.35 5.31 9.81 Hydrocarbon Type, vol % Aromatics 28.1 25.12 24.7 23.96 22.94 25.63 25.1 24.83 24.28 23.35 26.45 25.83 25.38 25 23.89 Olefins 5.08 5.19 5.12 4.83 4.72 0.52 0.52 0.49 0.48 0.41 0.14 0.12 0.09 0.11 0.13 n-Paraffins 11.06 11.07 10.82 10.64 10.11 9.71 9.66 9.36 9.18 8.77 3.42 3.39 3.32 3.22 3.13 l-Paraffins 40.51 40.48 39.63 38.93 36.95 48.71 48.21 47.12 45.95 43.82 67.64 67.36 65.77 64.19 81.03 Naphthenes 15.39 15.15 14.78 14.48 13.76 12.99 12.94 12.55 12.35 11.82 1.19 1.14 1.19 1.13 1.09 Base 7 +2 +4 +6 +10 Base 8 +2 +4 +6 +10 Base 9 +2 +4 +6 +10 Vapor Pressure, psi 6.9 7.8 7.9 7.9 7.9 6 7 7.1 7.2 72 5.8 6.7 6.9 6.9 6.9 D 86 Distillation, ° F. Initial 103 103 106 105 108 111 104 109 109 110 102 105 104 108 110  5% Evaporated 132 123 123 123 124 138 128 128 129 130 139 131 130 131 132 10% Evaporated 140 130 127 127 128 148 137 133 134 134 151 141 136 136 137 15% Evaporated 145 137 130 130 131 155 146 137 135 136 161 152 142 139 140 20% Evaporated 151 143 135 133 134 162 155 144 138 140 170 164 152 143 144 25% Evaporated 157 150 138 137 138 169 164 155 142 143 181 177 167 148 148 30% Evaporated 163 159 160 141 141 177 173 168 153 146 191 169 183 184 152 35% Evaporated 170 167 161 148 143 165 183 179 168 149 202 199 197 185 156 40% Evaporated 176 175 171 162 146 194 192 190 183 154 211 208 207 201 171 45% Evaporated 185 184 181 176 149 202 201 200 196 173 218 217 215 212 200 50% Evaporated 196 193 192 189 185 212 211 209 207 197 224 223 222 219 216 55% Evaporated 207 205 202 200 188 221 220 219 217 213 230 229 228 226 224 60% Evaporated 220 217 215 213 207 230 230 229 227 224 236 234 234 232 234 65% Evaporated 234 231 229 227 223 240 239 238 236 234 241 240 240 238 236 70% Evaporated 248 248 244 242 237 248 248 247 246 244 247 246 246 245 246 75% Evaporated 263 280 259 258 254 259 256 257 258 254 255 254 254 253 251 80% Evaporated 278 278 275 274 271 269 269 267 267 265 265 263 263 262 283 85% Evaporated 295 294 292 291 290 281 281 279 279 278 277 276 275 274 272 90% Evaporated 317 316 312 312 310 296 297 293 294 293 292 291 290 289 291 95% Evaporated 343 316 319 317 312 310 308 End Point 346 346 345 342 347 323 322 314 317 320 315 309 309 312 310 % Recovered 95.2 94.7 94.7 95 94.9 95.3 95.3 95.4 95.4 95.4 95 95 95 95 95.3 Temperature for a Vapor-Liquid 151 140 136 135 135 160 148 143 141 140 165 152 146 144 142 Ratio of 20, ° F. Ethanol, vol % 0 1.47 3.44 5.61 9.77 0 1.25 3.21 5.39 9.67 0 1.39 3.28 5.48 9.77 Hydrocarbon Type, vol % Aromatics 32.78 32.35 31.71 30.66 32.36 34.45 34.68 34.4 33.35 31.29 36.28 35.55 35.5 34.01 32.36 Olefins 0.43 0.42 0.4 0.41 0.17 1.41 1.47 1.42 1.37 1.3 0.23 0.23 0.24 0.16 0.17 n-Paraffins 11.52 11.27 11.08 10.88 5.63 11.31 11.01 10.77 10.59 10.21 6.43 6.33 6.14 6.1 5.83 l-Paraffins 41.03 40.25 39.39 38.79 47.23 37.1 36.08 34.92 34.42 33.16 52.04 51.52 50.05 49.38 47.23 Naphthenes 12.57 12.51 12.3 12.02 4.05 14.61 14.33 14.08 13.81 13.2 4.41 4.43 4.23 4.23 4.05

[0094] While the invention has been described with preferred embodiments, it is to be understood that variations and modifications may be resorted to as will be apparent to those skilled in the art. Such variations and modifications are to be considered within the purview and the scope-of the claims appended hereto. 

What is claimed is:
 1. A method for blending unleaded gasoline having an RVP of 8.0 or less, which comprises providing a substantially oxygenate free unblended gasoline blend stock which has an RVP of no greater than 7.0; and adding ethanol to the gasoline blend stock in an amount such that the final gasoline meets the California Code of Regulations, with the unleaded gas to which the ethanol is added having a T50 sufficiently high such that the ethanol addition does not cause T50 value to drop below the ASTM D 4814 minimum requirement of 170° F.
 2. The method of claim 1, wherein the RVP of the substantially oxygenate free blend stock is no greater than 6.5.
 3. The method of claim 1, wherein the RVP of the oxygenate free gasoline blend stock is no greater than 6.0.
 4. The method of claim 1, wherein the RVP of the substantially oxygenate free gasoline blend stock is in the range from about 6.0-7.0 psi.
 5. The method of claim 1, wherein the RVP of the substantially oxygenate free gasoline blend stock is in the range from about 6.0-6.5 psi.
 6. The method of claim 1, wherein the RVP of the substantially oxygenate free gasoline blend stock is in the range from about 5.5-6.0 psi.
 7. The method of claim 1, wherein the final unleaded gasoline has an RVP of 7.5 psi or less.
 8. The method of claim 1, wherein the RVP of the final gasoline is 7.0 psi or less.
 9. The method of claim 1, wherein the amount of ethanol added to the gasoline blend stock is at least 2.0 vol % based on the final gasoline.
 10. The method of claim 1, wherein the amount of ethanol added to the gasoline blend stock is in an amount of at least 4.0 vol %.
 11. The method of claim 1, wherein the amount of ethanol added to the gasoline blend stock is in an amount of at least 6.0 vol % based upon the final gasoline.
 12. The method of claim 1, wherein the ethanol is added to the gasoline blend stock at a location different from the location at which the blend stock was blended.
 13. A gasoline blend stock composition which contains less than 30 ppm sulfur, exhibits an RVP of less than 6.0 and a T50 of greater than 190° F.
 14. The method of claim 1, wherein a model is created for blending ethanol with the blend stock, and the blending is conducted consistent with the model. 